The Policy and Charging Control, PCC, architecture was introduced in 3GPP Rel-7 and has been further evolved in 3GPP Rel8 and Rel9. It provides operators with advanced tools for service-aware QoS and charging control.
For 3GPP Rel-10, there is currently a Study Item for Policy Enhancements that investigates various functional additions to the already existing architecture. Currently there are 4 key issues under investigation. One of those key issues is called “QoS and gating control based on spending limits”. This key issues looks into the case when the QoS (bandwidth) of an ongoing session must be throttled due to the fact that the user has reached some form of credit related limit. One example might be that the user is roaming (data services while roaming is often expensive and charged per Megabyte) and has a pre-defined safety limit of e.g. 50 Euros when the bandwidth should be set to a minimum until the user has been informed and once again agreed to be charged for another 50 Euros.
In the current PCC architecture, when a new PDN-connection is set up or when it is being modified, the PCEF (i.e. PDN-GW or GGSN) always queries the PCRF over the Gx interface, i.e. the interface between PCEF and PCRF, for a policy decision prior to requesting credit from the OCS over the Gy interface, i.e. the interface between PCEF and OCS. There are two alternatives defined for when credit requests over the Gy interface may take place according to the present 3GPP standard. One alternative is to request credits from the OCS over the Gy interface immediately at PDN-connection establishment, and another alternative is to delay the request of credit until an incoming payload packet is classified by the PCEF to an authorized service for which online charging applies.